Agent of the Inquisition

Slave to the Chalice. When Bloodied, this creature gains 10ft to all movement. Additionally, it may cast additional spells on his spell list, if it has any. Additionally, it may have 

Chaos Corrupted. When Bloodied, this creature changes his size to Large, changes his appearance to look demonic, and gains resistance to fire damage. This creature gains a 15ft visible aura that gives other monsters with the Slave to the Chalice trait advantage on Melee Attack Rolls.

Infernal thralldom. When this creature starts casting Infernal Calling, if it maintains concentration until the start of his next turn, he successfully casts it immediately, ignoring the 1 minute casting time.

Multiattack. The agent makes two attacks, using Lighting Blade, Lighting Blast or Infernal Punch in any combination.

Lightning Blade. Melee Attack Roll: +6, reach 5 ft. Hit: 12 (2d6 + 5) Slashing damage plus 14 (4d6) Lightning damage. If this creature is Bloodied, it cannot make this attack.

Lightning Blast. Ranged Attack Roll: +6, range 30/90 ft. Hit: 10 (1d10 + 5) Lightning damage. If this creature is Bloodied, the target of this attack must make a DC 15 Strength Saving Throw and receive 14 (4d6) Thunder damage, move 20 feet away from the attacker and be knocked Prone on a failure, or receive half as much damage on a success.

Infernal punch. Melee Attack Roll: +9, reach 5 ft. Hit: 22 (4d8 + 4) Bludgeoning damage plus 10 (4d4) Fire damage. The target of this attack must make a DC 15 Strength Saving Throw and receive 14 (4d6) Thunder damage, move 20 feet away from the attacker and be knocked Prone on a failure, or receive half as much damage on a success. This creature is unable to make this attack unless it is Bloodied.

Spellcasting. The agent casts one of the following spells, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 15):

At Will: Detect Thoughts, Eldritch Blast
3/Day Each: Expeditious Retreat ,Thunder Step, Hellish Rebuke, Burning Hands only when bloodied
1/Day Each: Steel Wind Strike, Infernal Calling only when bloodied

Quick Spellcaster. As a bonus action, this creature may cast a spell on its spell list, as long as it has not cast a spell this turn. If a spell is cast as a bonus action, if it has a required casting time of 1 Action, it instead has a casting time of Bonus Action.

Expeditious Retreat: As a bonus action, this creature can cast Expeditious Retreat.

Hellish Rebuke. As a reaction, this creature can cast Hellish Rebuke.